1. Field of the Invention
The present invention relates to the field of storing and conveying fluids, and more particularly, to an improved system and method for storing and conveying fluids, such as potable water, by means of a collapsible, floating and towable container. Furthermore, this invention relates to methods for filling and/or emptying and retrieving and/or deploying such containers.
2. Description of the Related Art
Although approximately two thirds of the surface of the Earth is covered by water, many areas and regions around the world are severely affected by the lack of this fundamental natural resource. People living in regions in the Middle East and in Northern Africa are today in need of reliable water supply for nutrition (food and drink), irrigation (agriculture) and sanitation purposes. Also, large areas in Asia, China and the Americas are threatened by lack of water, due to high population density compared to the available local water resources. Furthermore, local water resources in several areas are unfit for human use, due to pollution and contamination.
In addition to the aforementioned uneven distribution of water as such, fresh water, i.e. water suitable for e.g. human and animal consumption and sanitary use, is even more scarce on a world wide basis. Only about 3.5% of the Earth""s surface water is fresh water, and almost all of that fresh water is in the form of ice, predominantly in the Arctic and Antarctic regions. According to Philip Ball, author of xe2x80x9cH2O: A Biography of Waterxe2x80x9d (Weinfelds and Nicolson, 1999, ISBN 0 297 64314 2), only approximately 0.01% of the Earth""s fresh water is in a form available for human and animal use, in the form of lakes, streams, rivers and groundwater aquifers. However, only half of this amount is directly accessible. Scientists have estimated that the global population presently is using more than half of the accessible fresh water. If the current trends persist, scientists predict, the demand for water on a global basis might exceed the total available supply by around the year 2030.
Despite substantial wide efforts to improve fresh water accessibility, including e.g. water management programs and desalination, there is still a need for a redistribution of water supplies. Although solar power will contribute to lowering the cost of desalination, this process is still very energy demanding and thus prohibitively costly for many third world countries.
In one type of redistribution effort, water is transported by sea over considerable distances, by means of ocean going tankers and barges. This method is very expensive, however, and can only handle relatively small volumes. One other means of transporting fresh water, which is considerably less expensive, is the use of large bags which are towed in a semi-submersed state, by one or more tugs. Commercial operations using such bags have been established; one example being the ongoing shipment of fresh water from Turkey to Northern Cyprus, undertaken by the applicant for the present invention.
As the process of transporting water in floating and towable fabric bags is still fairly new, the associated technology is still not developed to a satisfactory state. Examples of shortcomings with the present water bag technology, are poor fabric rupture control, cumbersome hose pull in- and connection procedures, inadequate towing capabilities and retarding/mooring problems.
Prior art water bags have no means for controlling or limiting fabric rupturing. Thus, a tear occurring in prior art bags may very rapidly propagate along a substantial length of the bag, leaving no option for the operator but to discard the bag. Repairing extensive tears is prohibitively costly.
Prior art water bags are towed by the connector element, which is attached to the front end of the bag. Thus, the operation of connecting and/or disconnecting prior art water bags to water filling- and/or discharge facilities, involves the launching of a filler/discharge hose from the filling/discharge facility, and performing the connection/disconnection in the sea. This operation is cumbersome, time-consuming, labor demanding and unreliable.
Prior art water bags are, while on tow and due to their considerable mass, in certain situations difficult to maneuver and control. This is a particularly crucial problem when the water bag needs to be decelerated and brought to a complete stop prior to connection to the onshore facility. Prior art water bags lack adequate means for retarding prior to connection, and also for adequate mooring during fresh water filling or discharge.
It is therefore a long felt need for an improved system for transporting large quantities of water over considerable distances, at affordable costs.
The present invention solves that need, in that it provides a system and method for transporting fluids in towable, floating bags, which provides better rupture control, improved handling characteristics and quicker pull in- and connection operation. Additionally, the invention provides novel methods for filling and emptying such water bags in order to ensure that the water bags do not sink to the seabed before, during and after filling.
These and other objects and features of the invention are provided by an improved system for storing and conveying fluids, where the system is adapted for towing by marine crafts in offshore conditions. In general, the system comprises:
a collapsible fluid container with an elongate shape and a first and a second end;
a fluid conduit fixedly attached to the front end of the container;
towing/mooring means fixedly attached to said conduit;
retarder/mooring means attached to said container second end; and
container retrieval, storage and deployment means.
Furthermore, an improved system and method for towing collapsible, floating, fluid containing containers is provided, where such system for towing comprises a fluid filling and emptying conduit attached to said container first end, and towing means attached to said conduit, and where the method comprising the towing of said container by means of pulling a fluid filling and emptying conduit attached to said container first end.
Furthermore, it is provided a method for emptying and retrieving a collapsible fluid container filled with a volume of fresh water, thus:
while the conduit is attached to an emptying facility, attaching the container second end to a container retrieval storage and deployment means removeably mountable on a vessel intended for the transportation of said container in an empty state;
coordinated with the discharge of said fresh water through said conduit, reeling said container onto said retrieval, storage and deployment means;
coordinated with the reeling of said container onto said retrieval, storage and deployment means, propelling said vessel in a direction generally towards said facility; and
when said container is sufficiently empty, releasing said hose from said facility, thereby enabling the part of said container and said hose still in the water to be completely retrieved onto said retrieval, storage and deployment means,
whereby said method effectively causes virtually said entire volume of fresh water to be emptied from said container.
Furthermore, it is provided a method for deploying of, and filling with an volume of fresh water, a collapsible fluid container, thus:
pulling the conduit off a container retrieval, storage and deployment means removeably mountable on a vessel intended for the transportation of said container in an empty state;
connecting said conduit to a filling facility and commencing a filling of fresh water through said conduit and into said container;
coordinated with the filling of said fresh water through said conduit, reeling said container off said retrieval, storage and deployment means;
coordinated with the reeling of said container off of said retrieval, storage and deployment means, propelling said vessel in a direction generally away from said facility; and
when said container is sufficiently filled with fresh water, releasing said container second end from said retrieval, storage and deployment means.
Preferred embodiments are contained within the accompanying claims.
Other features, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of a preferred embodiment which follows, when taken in conjunction with the accompanying drawings.